Liquid-sealed lifter roof for fluid storage apparatus



March 27, 1951 Y J. WIGGINS 2,546,573

LIQUID-SEALED LIFTER ROOF FOR FLUID STORAGE APPARATUS Filed Feb. 13,1946 2 SheetsSheet 1 IN VEN TOR JOHN H. W/GG/NS March 27, 1951 J H.WIGGINS 2,546,573

LIQUID-SEALED LIFTER ROOF FOR FLUID STORAGE APPARATUS Filed Feb. 13,1946 2 Sheets-Sheet 2 Patented Mar. 27, 1951 LIQUID-SEALED LIFTER ROOFFOR FLUID STORAGE APPARATUS John H. Wiggins, Chicago, Ill.

Application February 13, 1946, Serial No. 647,385

This invention relates to fluid storage apparatus of the particulartype, that comprises a tank or equivalent stationary container having aside wall, a lifter roof, or vertically-movable roof for said tankprovided with a skirt, dip ring or side wall portion arranged intelescopic relationship with the tank side wall, and a liquid seal forsaid roof composed of a reservoir extending circumferentially around thetank side wall and containing a liquid sealing medium, in which the sidewall portion of the roof is immersed.

One object of my present invention is to providea fluid storageapparatus of the general type mentioned, which is of such design orconstruction, that it is commercially practicable or feasible to usefuel oil as the liquid sealing medium.

Another object is to provide afluid storage apparatus of the particulartype mentioned, in which the liquid sealing medium is effectivelyprotected from the atmosphere.

Another object of my invention is to provide a fluid storage apparatusof the particular type mentioned, which is of such construction that theliquid sealing medium is prevented from evaporating into the atmosphere.

And still another object of my invention is to provide a fluid storageapparatus of the kind above mentioned, in which the reservoir that holdsthe liquid sealing medium is provided at 1 its upper end with aneflicient closure of inexpensive construction, which, in addition toreducing evaporation losses and preventing the liquid sealing mediumfrom becoming a fire hazard, also prevents snow and substantialquantities of rain water from entering said reservoir. Other objects anddesirable features of my invention will be hereinafter pointed out.

In liquid-sealed lifter roofs of conventional design, used for volatilepetroleum products, the roof is provided adjacent its peripheral edgewith a depending tubular Weather shield that surrounds the reservoir forthe sealing liquid and prevents rain from beating into said reservoir,but no means is provided for protecting the liquid sealing medium fromthe atmosphere, or for preventing air from entering the upper end ofsaid reservoir and circulating in contact with that portion of thesurface of the sealing medium which surrounds or is located outside ofthe depending side wall of the portion immersed in the liquid sealingmedium. Consequently, if fuel oil or any non-volatile petroleum productis used to constitute the liquid-sealing medium of a storage apparatusfilled with gasoline or other highly 3 Claims. (Cl. 48176) volatilematerial, then by laws of absorption of vapors, it is possible for saidnon-volatile product to become saturated with the highly volatilefractions of the gasoline stored in the apparatus, thereby convertingthe liquid-sealing medium (the fuel oil in the reservoir) into asubstance that evaporates rapidly and which constitutes a dangerous firehazard, due to the fact that it consists of a highly inflammable liquidover which air currents are constantly circulating. In an oil storagetank having a diameter of approximately ft. and provided with a lifterroof that is capable of rising and falling a distance of approximately10 ft., it is necessary to use nearly 3,000 gallons of fuel oil for theseal, whose cost after installation is in excess of approximately$1,200.00. There is considerable gasoline loss, caused by absorption ofgasoline vapors at the surface of the fuel oil seal and gasolinecondensation on the inner side of the depending side wall portion of theroof that runs down said side wall portion and mixes with the fuel oilin the reservoir, such gasoline condensation on the inner surface of theside wall portion of the roof tending to cause the fuel oil seal tobecome supersaturated with gasoline. seal always constitutes a firehazard, inasmuch as the constant rise and fall of the lifter roof actsas a means to thoroughly mix the lighter and heavier fractions of thesealing oil, thus assuring that a mixture containing volatile fractionsis exposed to the air side of the reservoir.

The apparatus herein described, which constitutes my invention,overcomes or eliminates the above mentioned objectionable features orcharacteristics of liquid sealed lifter type tank roofs of conventionaldesign, inasmuch as it comprises a closure for the reservoir which holdsthe liquid sealing medium, constructed and arranged so that it protectsthe sealing liquid from the atmosphere, prevents snow and substantialquantities of rain water from entering the reservoir, and \performs theabove functions efficiently without interfering with or retarding thevertical movement of the side wall portion of the roof during the riseand fall of the roof. In the preferred form of my invention hereinillustrated, the above mentioned closure is formed by an annular membermade of gas-tight material, whose outer edge is attached to the outerwall of the sealing liquid reservoir, and whose inner edge is arrangedin sliding engagement with the outer side of the depending side wallportion on the roof, the inner edge portion of said annular, flexibleclosure being sustained by a supporting Moreover, the fuel oil 7 meansthat presses said inner edge against the depending side wall portion onthe roof.

Figure 1 of the drawings is a vertical transverse sectional view of aliquid-sealed, lifter type tank roof constructed in accordance with myinvention.

Figure 2 is an enlarged fragmentary vertical sectional view through thereservoir that holds the liquid sealing medium, showing the normalposition of the flexible closure at the upper end of said reservoir.

Figure 3 is a View similar to Figure 2, showing how the rockablecarriers which support the inner edge portion of the closure are capableof moving radially so as to compensate for or provide for relativemovement between the reservoir and the depending side wall portion onthe roof; and

Figure 4 is a vertical sectional view, taken on approximately the line44 of Figure 2, looking in the direction indicated by the arrows, so asto show the gaps or spaces between the horizontallydisposed, supportingbars on the rockable carriers and also to illustrate how said carrierscan move circumferentially, to the right or to the left, to compensatefor relative movement between the reservoir and the side wall portion ofthe roof, when either one of said parts goes out of round.

In the drawings, A designates the side wall portion of a tank that isadapted to be used for storing a fluid, usually gasoline or some otherhighly volatile material, .B designates a lifter roof orvertically-movable roof for said tank, C designates a depending sidewall portion, skirt or dip ring on said roof, arranged in telescopicrelationship with the tank side wall, D designates an annular reservoir,herein illustrated as being attached to the side wall A of the tankadjacent the top edge of .same and proportioned so that the annularouter wall of said reservoir will surround the side wall portion C ofthe roof, at designates a liquid sealing medium in the reservoir D,such, for example, as fuel oil, in which the side wall portion C of theroof is immersed, and E designates as an entirety a roof supportingstructure inside of the tank, composed of a center post that supports aplurality of radiallydisposed rafters Whose outer ends are attached tothe tank side wall A at the top edge of same.

The previously mentioned closure for the upper end of the sealingliquidreservoir D, preferably consists of a gas and liquid-tight, flexiblemember F, of annular form, whose outer edge or peripheral edge isattached by a clamping plate I to the top edge of the outer side wall ofthe reservoir D, and whose inner edge is maintained in slidingengagement with the outer surface of the depending side wall portion Cof the roof. Preferably, the free edge or inner edge of the closure F issustained by a supporting means that comprises a plurality of rockablecarriers G, pivotally mounted on the inner side of the outer wall of thereservoir D in such a way that said carriers are capable of movingradially inwardly and outwardly to compensate for or provide forrelative radial movement between the outer side wall of the reservoirand the depending side wall portion C of the roof, as shown in Figure 3,and are also capable of moving circumferentially a limited distance tothe right and to the left, as indicated by broken lines in Figure 4, soas to provide for relative movement between the reservoir and thedepending side wall portion C on the roof when either of said parts goesout of round. At the upper end of each of the carriers G there is ahorizontally-disposed, arc-shaped supporting bar 3 and a co-actingarc-shaped clamping bar 4, that support and grip the closure F at apoint adjacent the inner edge of said closure, the clamping bars 4 beingretained in position by nuts 5 on threaded studs or bolts 5 that projectupwardly from the supporting bars 3 and extend through holes in theclosure F. The arc-shaped supporting bars 3 and their coacting clampingbars 4 are not in abutting engagement with each other, but instead, theends of the bars 3 and the ends of the bars 4 are separated by spacesusually of about one inch in length, as shown in Figure 4 of thedrawings.

Due to the fact that the inner edge of the closure F is of considerablyless diameter than the outer edge of said closure, I prefer to form theinner edge portion of the closure F from a relatively narrow,annular-shaped piece of gas-tight fabric F that will lie substantiallyflat on the supporting bars 3 of the carriers G, and form the remainderof the closure F from a separate, annular-shaped, relatively wide pieceof fabric that forms, in effect, a curtain-like closure that bridges thegap between the outer wall of the reservoir D and the inner edge portionF of the closure that is in sliding engagement with the depending sidewall portion C of the roof. The inner edge portion F of the closure Fconstitutes a continuous, annular wiper of substantially fixed length,which, during the upward movementof the roof, will flex upwardly, andthus remain in snug wiping engagement with the side wall portion of theroof, and which, on the succeeding downward movement of the roof, willreverse or flex in the opposite direction. Said wiper F can vary itslength by stretching or compressing in the one inch gaps between thesupporting bars 3 of the carriers G. However, said wiper F has to changein circumference, but very little, since the side wall portion C of theroof is of the same circumference from its upper to its lower end. Thewide, annular-shaped member, which constitutes the curtain-like,flexible portion of the closure F that bridges the gap between the wiperF and the outer wall of the reservoir D, is of considerably greaterdiameter at its outer edge than at its inner edge. Consequently, whensaid part is being combined with the supporting and clamping bars of thecarriers G, its inner edge must be folded or wrinkled sufficiently tomake said inner edge of substantially the same diam eter as the outeredge of the wiper F when said parts are interposed between and clampedtogether by the bars 3 and 4 of the carriers G. Said wrinkles or foldsare manually formed, and by pressure between the bars 3 and i, areironed out, so that a gas-tight connection is made between therelatively narrow, annularshaped member, which-constitutes the wiper Fof the closure F and the relatively wide, annular-shaped membe whichconstitutes the remainder of'the closure for the upper end of thereservoir D. At the gaps between the ends of the supporting bars 3 ofthe carriers, the two pieces of fabric that constitute the flexibleclosure F are cemented together, thus forming, in effect, agas-tight'cloe sure that cuts off communication between? the atmosphereand the space above that portion of the surface of the liquid sealingmedium which surrounds or is located outside of the depending side wallportion C 'onthe roof. Since the wiper F is a substantially fixedlengthmembe y -then in case the side wall portion C on the roof goesoutof round, the wiper F'- will slide circumferentially relatively tothe side wall portion C .of-the roof, due to the fact that the carriersD are pivotally mounted in such a way that, in addition to being capableof moving radially, inwardly and outwardly, they are also capable ofrocking laterally a limited distance to the right and to the left, asindicated in dotted lines in Figure 4.

While I prefer to form the closure F for the reservoir D in the mannerabove described, due to the fact that such a closure is inexpensive toconstruct and easy to install, I wish it to be understood that my broadidea contemplates using any kind of a closure that will effectively outoff communication between the atmosphere and that portion of the surfaceof the liquid sealing medium which surrounds and is located outside ofthe depending side wall portion C on the roof, and at the same timeprovide for the rise and fall of the roof. As previously described, sucha closure prevents snow from beating into the reservoir D, and itprevents substantial quantities of rain water from entering saidreservoir. As a safety measure, the reservoir D can, if desired, beprovided with a water discharge device for removing Water from saidreservoir, such, for example, as rain water that finds its way into thereservoir through the joint between the wiper F and the side wallportion C of the roof, or water of condensation that collects on theinner surface of said side wall portion and precipitates through theliquid sealing medium as to the bottom of the reservoir D, theabove-mentioned water discharged device being herein illustrated as aninverted syphon drain I-I attached to the bottom of the reservoir D, asshown in Figure 1.

Having thus described my invention, what I claim and desire to secure byLetters Patent is: 1. A fluid storage apparatus, comprising a tankadapted to hold a fluid that is being stored and provided with astationary side wall, a verticallymovable roof for said tank providedwith a depending skirt arranged in telescopic relationship with the tankside wall, a reservoir provided with an outer wall that extendscircumferentially around the tank side wall said reservoir being adaptedto contain a liquid sealing medium that is separate and distinct fromthe stored fluid in the tank, the depending skirt on the roof beingimmersed in the liquid sealing medium in said reservoir, a flexibleclosure at the upper end of the reservoir attached at its outer edge tothe outer wall of the reservoir and having its inner edge portionarranged in sliding engagement with the outer surface of the dependingskirt on the roof and radially-movable carriers mounted on the outerwall reservoir and attached to said flexible closure for supporting theinner edge portion of same that is arranged in sliding engagement withthe depending skirt on the roof.

2. An apparatus of the kind described in claim 1, in which said carriersare attached to the reservoir by pivotal connections which haveprovision for permitting said carriers to move circumferentially alimited distance to the right and to the left, so as to provide forrelative circum ferential movement between the reservoir and thedepending skirt on the roof when either of said parts goes out of round.

3. An apparatus of the kind described in claim 1, provided with meansfor automatically discharging 'from the lower end of said reservoir,rain water or water of condensation that has entered the upper end ofthe reservoir and precipitated through the liquid sealing medium in thereservoir.

JOHN H. WIGGINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,892,144 Grifiin Dec. 2'7, 19322,180,587 Hammeren Nov. 21, 1937 2,302,904 Wiggins Nov. 24, 19422,344,436 Laird Mar. 14, 1944

